"a safeguard," c. 1600, originally (late 14c., Palladioun) "a sacred image of Pallas Athene," from Old French palladion, from Latin palladium, from Greek Palladion, noun use of neuter of Palladios "of Pallas." It stood in the citadel of Troy and the safety of the city was believed to depend on it. Related: Palladian.